How Can Data Be Recovered? An Explanation For The Non-Technical Person

Digital storage devices with amazing storage capacities are flooding the markets regularly. However, inspite of the increase in the reliability of these storage devices, loss of data seems to be a very common phenomenon. The major cause of loss of data is usually human error, but there can be other reasons as well:
1. Accidental deletion of a file or folder
2. File system format
3. Logical damage of a file system
4. Loss of information about partition
5. Storage failure
To understand how data recovery works lets first take a look at the basics. When you first delete some data it is sent to the recycle bin. This means that you can always restore the file or data back to its original location. When you delete some data, what the computer does is that it just removes the path which provides the access to the data. The data is still there and can be accessed again once the path to the data is provided yet again.
But what if the data is deleted from the recycling bin as well or if it is deleted using the 'SHIFT-DEL' procedure which removes the data permanently? In that case as well the path to the data is removed and the data still exists somewhere on your computer's hard drive. The only difference now is that the data is in danger of being over-written by some other data.
So, unless the data which you have deleted is not over-written by some new data, you can recover it using dedicated software. This software scans the entire hard drive for information which is to be specified by you and this program re-assembles the structures of the deleted data. However, if you store newer data, then the chances of recovering the old deleted data become slimmer. Traces of the old data may exist on the hard drive but it may then become impossible to recover the whole file.
If we consider an analogy, take the example of a book which you do not need anymore and which you wish to recycle. For this purpose, you place the book in a recycling bin. This is analogous to the computer's recycle bin - you can restore the book back whenever you wish to.
Now, when you hand over the book to the recycling company, they first tear apart the pages of the book. At this point as well the book can be recovered by just joining together the pages. However, when the pages are initiated into the recycling process then it is impossible to recover them. The same is true for digital data. It is recoverable up to a certain point beyond which it becomes very hard or impossible to recover it. Sometimes the deleted data may remain stored on your hard-drive for years if you do not store a significant amount of new data and sometimes the deleted data may be totally wiped off by overwriting it with new data.

by Jesse P

photo credit: Derek K. Miller via photopin cc